Review and Measurements of New JDS Labs Atom Headphone Amp

[Haze]

5V is too low to cause any damage. The regulated voltage should go higher than 20V with stock supply. I'm pretty sure if you do the other way plugging in the 15V ac supply to one that takes 5V it will be smoke...
It looks like there's a voltage senser that is waited to be triggered to close the relay. Maybe higher voltage would lead to the amp outputting DC, I'm not sure.

Thank you. That is a relief.

 

[MrOtto]

16V is the normal voltage? Inputing a lower voltage DC shouldn't harm anything?

 

[Sandbo]

Sorry but I have a silly question:
I connected the Atom amp's RCA output to my PC speakers. Though the speaks are inferior and how it is setup is probably not important, I want to understand the optimal approach of powering the speakers.

Current setup
-DAC (Topping D10s) is set to 100% in Windows
-Atom amp is set to 50% volume
-Volume controlled through the speaker's front knob

But I also understand that it is better to maximize gain at an earlier stage of the chain, so should I change it to the below?
-Atom amp is set to 100% volume
-Volume controlled through the speaker's front knob

But will then it means I am operating the Atom amp in a gain region where SNR is lower (naively I guess max gain output could perform worse)?
Or I might risk saturating the amplifier?

 

[AnalogSteph]

Not a silly question at all, actually.

I suspect you could trade level between D10s and Atom to a considerable degree, as both are fairly to very low-noise devices, while your speakers' electronics may not be nearly as much.

For choosing speaker input level, I would first determine the point of the speaker volume control at which output noise begins to audibly rise (no input signal - Atom volume at minimum). Then see whether you can achieve the highest output level you would ever want without any distortion. This may not be feasible but should at least help you dial in levels at the speaker end.

I would set DAC volume to about 80% or so, as I think ESS DACs will hard-clip at 0 dBFS with no headroom. You may not have to do this if you have playback level normalization (e.g. ReplayGain) turned on, as headroom for intersample-overs is generally needed most for material that's quite loud anyway.

Quite honestly, you may well be able to simplify the chain by using a Y splitter cable out of the DAC to connect both Atom and speakers in parallel, thus taking the Atom out of the picture during speaker operation - quite likely to no apparent sonic detriment, while making operation a lot easier (not to mention giving you the ability to choose headphone amp gain and volume freely, only depending on the headphone's needs). Juggling three volume controls in series is in no way user-friendly, especially when you can trade off between the first two to a substantial degree without any apparent effect on the output whatsoever.

Multi-stage volume controls only get you anything when your last amplifier stage is low in noise and easily swamped by noise from the previous stage with volume wide open. A Hi-Fi power amplifier will often qualify, a PC speaker system very well may not. Needlessly adding complexity and inconvenience doesn't make any sense either.

 

[Sandbo]

Not a silly question at all, actually.

I suspect you could trade level between D10s and Atom to a considerable degree, as both are fairly to very low-noise devices, while your speakers' electronics may not be nearly as much.

For choosing speaker input level, I would first determine the point of the speaker volume control at which output noise begins to audibly rise (no input signal - Atom volume at minimum). Then see whether you can achieve the highest output level you would ever want without any distortion. This may not be feasible but should at least help you dial in levels at the speaker end.

I would set DAC volume to about 80% or so, as I think ESS DACs will hard-clip at 0 dBFS with no headroom. You may not have to do this if you have playback level normalization (e.g. ReplayGain) turned on, as headroom for intersample-overs is generally needed most for material that's quite loud anyway.

Quite honestly, you may well be able to simplify the chain by using a Y splitter cable out of the DAC to connect both Atom and speakers in parallel, thus taking the Atom out of the picture during speaker operation - quite likely to no apparent sonic detriment, while making operation a lot easier (not to mention giving you the ability to choose headphone amp gain and volume freely, only depending on the headphone's needs). Juggling three volume controls in series is in no way user-friendly, especially when you can trade off between the first two to a substantial degree without any apparent effect on the output whatsoever.

Multi-stage volume controls only get you anything when your last amplifier stage is low in noise and easily swamped by noise from the previous stage with volume wide open. A Hi-Fi power amplifier will often qualify, a PC speaker system very well may not. Needlessly adding complexity and inconvenience doesn't make any sense either.

Thanks for your detailed explanations.

I tried to listen to the noise of the speakers, surprisingly I couldn't hear any noise at max volume (when PC isn't making any sound, and DAC/Amplifier are still on.) The 80% mark makes sense, if there is no headroom for the DAC this might be necessary. For the Y-splitter, this is a good suggestion, I might get one later, but at the moment I use less often my headphone so it is not too inconvenient.

 

[Haze]

Well I found what the problem with my Atom is. It's the Khadas Tone Board. It's causing the Atom to distort. It's very noticeable at high volumes on songs that have long sustained notes. They "wobble" if you get my meaning. Kind of reminds me of vinyl flutter only less severe. I fished out my Topping D10 and it had no such issues connected to the Atom.

Any idea's why this might be? Is it possible the Tone is putting out slightly too much power for the Atom?

 

[AnalogSteph]

The Tone Board doesn't have outlandishly high output, and what you describe sounds like a compressor / limiter anyway (like the one in the Windows sound stack). My guess is excessive digital levels. Check your playback chain, notably any APOs. Equalizer-APO for example could be installed for one device but not another, thus explaining the difference.

 

[half_dog]

Well I found what the problem with my Atom is. It's the Khadas Tone Board. It's causing the Atom to distort. It's very noticeable at high volumes on songs that have long sustained notes. They "wobble" if you get my meaning. Kind of reminds me of vinyl flutter only less severe. I fished out my Topping D10 and it had no such issues connected to the Atom.

Any idea's why this might be? Is it possible the Tone is putting out slightly too much power for the Atom?

Try to reflash its firmware (or a new version) and reinstall its USB driver. I think I've seen someone talking about some boards with corrupted firmware. Do you have a USB audio interface? If yes you could measure KTB's output and check if there is any clipping. Another thing, KTB is sensible to USB noise at some point, a usb shielded cable can help a little - I'm using an USB cable from a Moto G7 Plus.

 

[Haze]

The Tone Board doesn't have outlandishly high output, and what you describe sounds like a compressor / limiter anyway (like the one in the Windows sound stack). My guess is excessive digital levels. Check your playback chain, notably any APOs. Equalizer-APO for example could be installed for one device but not another, thus explaining the difference.

It was still the same when testing with ASIO and WASAPI. That would rule out something the Windows sound stack right?

 

[Tortie]

I was about to order an Atom. I go through the checkout process and what do I see? JDS has an extra fee which they call "insurance". This is a perfect example of nickel and diming. Insuring a package for a retail transaction should (and almost always is!) the responsibility of the merchant. Not the customer.

I love the little pop up tool tip when you click on the "?" mark. JDS wipes their hands of responsibility for their own shipments.

Bottom line here is that the $99 price point for the Atom must no longer financially feasible for them due to inflation or rising shipping costs. So instead of raising the price of the Atom a couple bucks they resort to this nonsense.

 

[Veri]

I was about to order an Atom. I go through the checkout process and what do I see? JDS has an extra fee which they call "insurance". This is a perfect example of nickel and diming. Insuring a package for a retail transaction should (and almost always is!) the responsibility of the merchant. Not the customer.

I love the little pop up tool tip when you click on the "?" mark. JDS wipes their hands of responsibility for their own shipments.

Bottom line here is that the $99 price point for the Atom must no longer financially feasible for them due to inflation or rising shipping costs. So instead of raising the price of the Atom a couple bucks they resort to this nonsense.

Well it's just ~$1.50 haha. If you want some easy discount check out their B-stock which is immaculate from my experience, just returned units
https://jdslabs.com/product/atom-amp/?viewing_bstock=true

 

[Doodski]

I was about to order an Atom. I go through the checkout process and what do I see? JDS has an extra fee which they call "insurance". This is a perfect example of nickel and diming. Insuring a package for a retail transaction should (and almost always is!) the responsibility of the merchant. Not the customer.

View attachment 115832

I love the little pop up tool tip when you click on the "?" mark. JDS wipes their hands of responsibility for their own shipments.

Bottom line here is that the $99 price point for the Atom must no longer financially feasible for them due to inflation or rising shipping costs. So instead of raising the price of the Atom a couple bucks they resort to this nonsense.

I've seen a extra insurance option at several retailers/etailers and I checked with the postal corp and they charge extra for insurance.

 

[Tortie]

I clicked on the 'More information' hyperlink and got the following. Now I'm confused. The wording is uh, strange. Customs delays? I live in the same country as JDS Labs. What the...

 

[Tortie]

I've seen a extra insurance option at several retailers/etailers and I checked with the postal corp and they charge extra for insurance.

Name an example.

 

[Tortie]

Well it's just ~$1.50 haha. If you want some easy discount check out their B-stock which is immaculate from my experience, just returned units
https://jdslabs.com/product/atom-amp/?viewing_bstock=true

I know lol. Like why even have that fee and put scary language in there. Just roll it into the main shipping fee like most retailers do. It's counterproductive to break it out separately. Curious what the logic is.

 

[Tortie]

I'm going to email them and ask if this insurance fee applies to me. The FAQ for the "Insurance" focuses heavily on international shipments. Maybe this fee is intended for foreign bound shipments?

 

[jseaber]

I know lol. Like why even have that fee and put scary language in there. Just roll it into the main shipping fee like most retailers do. It's counterproductive to break it out separately. Curious what the logic is.

Thanks for pointing this out. The shipping insurance checkbox has been part of our checkout system for about a decade. It should be clear from the data below who the strong wording is targeted towards. That said, we removed USPS First Class Intl at the onset of the pandemic, when USPS loss rates climbed from around 3% to 10%. The strong wording is no longer necessary, as other carriers are far more reliable.

Anyway, I'll share your feedback with our web team. Probably best to delete the checkbox now that we've eliminated the unreliable service.

Delivery Success of all JDS Labs shipments in 2020

FYI - Lost packages from UPS and FedEx were primarily porch piracy.

 

[Veri]

Thanks for pointing this out. The shipping insurance checkbox has been part of our checkout system for about a decade. It should be clear from the data below who the strong wording is targeted towards. That said, we removed USPS First Class Intl at the onset of the pandemic, when USPS loss rates climbed from around 3% to 10%. The strong wording is no longer necessary, as other carriers are far more reliable.

Anyway, I'll share your feedback with our web team. Probably best to delete the checkbox now that we've eliminated the unreliable service.

Awesome answer and fast, as I expect from JDS cheers for sharing those data

 

[Tortie]

Thanks for pointing this out. The shipping insurance checkbox has been part of our checkout system for about a decade. It should be clear from the data below who the strong wording is targeted towards. That said, we removed USPS First Class Intl at the onset of the pandemic, when USPS loss rates climbed from around 3% to 10%. The strong wording is no longer necessary, as other carriers are far more reliable.

Anyway, I'll share your feedback with our web team. Probably best to delete the checkbox now that we've eliminated the unreliable service.

Delivery Success of all JDS Labs shipments in 2020

View attachment 115838

FYI - Lost packages from UPS and FedEx were primarily porch piracy.

Thank you for explaining the insurance fee better. I think some State Side customers might've misconstrued the language in the pop-up tool tip and checked the box. I probably would have if I was in a rush.

I placed my order and I'm looking forward to using the Atom.

 

[Veri]

I placed my order and I'm looking forward to using the Atom.

Neat~ hope this amp will serve you well Tortie haha